Al-Cu合金中PLC效应时域和空域行为的实验研究

在不同拉伸应变速率下，得到了Al-Cu合金中PLC(Portevin-Le Chatelier)效应在时域上的三类“锯齿形”应力一时间曲线，比较并研究了三种曲线的异同及其产生的定性解释．与之相对应，观察并分析了PLC效应空域上三种类型PLC变形带的空间传播特性．针对3mm厚的试件，探讨了在不同拉伸应变率下，类型A和B的PLC变形带的传播速率随变形过程的演化；得到了在相同应变下，变形带的传播速率和加载应变速率之间的幂律关系．同时，还将时域上的“锯齿形”应力一时间曲线与空域上的带的传播位置时间曲线相对应，得到了PLC效应发生时宏观上时域和空域之间的关系、另外，还讨论了试件厚度对PLC变形带的空间相关性的影响．

Experimental Investigations on the Temporal and Spatial Behaviors of the PLC Effect in Al--Cu Alloys

The temporal and spatial behaviors of the PLC (Portevin-Le Chatlier) effect in Al-Cu alloy are systemically investigated and analyzed. Under different applied strain rates, three types of serrated stress-time curves are obtained respectively. And the similarities and differences of them are compared and interpreted qualitatively. Correspondingly, the spatial propagating characteristics of the three types of PLC deformation bands are observed and analyzed. The evolutions of the propagating velocity for type A and B bands are discussed with respect to different tensile strains in the 3mm thick specimens. At the same tensile strain, the power law relationship between band propagating velocity and applied strain rate is also obtained. Contrasting the serrated stress-time curves with the position-time plots, the relationship between the macroscopic spatiotemporal behaviors is compared for the PLC effect. The influence of specimen thickness to the spatial correlation of PLC deformation bands is also discussed.